Evaporative cooler pads have been commercially used for many years as an economical substitute for air conditioning. Typically, a pad of wood shavings or other fibrous material is wetted while air is drawn therethrough. The passing air evaporates the water and cools the air for use in a residence or other building interior.
For years, the most commercially available pads were formed from a batt of natural cellulosic lightweight elongate segments such as aspen wood shavings. These pads not only could be produced efficiently and inexpensively, but also they retained an evaporative efficiency of up to fifty percent since the cellulosic elongate segments were hydrophilic.
A more recent evaporative cooler pad invented and marketed by the assignee of this invention and disclosed in U.S. Pat. No. 4,556,521 to Baigas, Jr. is now commercially available. This pad increases the evaporative efficiency of a cooler pad up to as high as eighty percent which is a marked improvement over prior pads made from natural cellulosic segments. A high loft batt of hydrophobic textile fibers such as polyester fibers are prebonded together and then coated with a preformed hydrophilic foam which substantially coats the bonded synthetic fibers of the batt and also bridges and spans random portions of the interstices and passageways of the batt to substantially increase the available surface area for contact by water. In addition, the preformed foam has a minute cellular structure which serves to produce a capillary type effect when contacted by water so that the water is wicked along the foam area to optimize the cooling efficiency of the pad. The foam acts to increase the evaporative efficiency of the batt from an essentially non-evaporative batt of hydrophobic fibers to an evaporative cooler pad having as high as about eighty percent evaporative efficiency.
Although these foam coated textile evaporative cooler pads have proved commercially successful, natural cellulosic evaporative cooler pads are still marketed and preferred by some because of their lower cost and market availability or an individual's preference. However, such natural cellulosic evaporative cooler pads are less efficient than the foam coated textile counterpart. If the thickness of the natural cellulosic pad is increased, the amount of evaporative cooling ability per square yard can be increased to give a cooling potential equal to the more efficient foam coated textile pads. This is possible, but not always desirable since shipment and handling is not facilitated by the increased thickness. In addition, the overall cost of the pad is increased. Also, some evaporative coolers may be designed to accept only thin pads making the use of thick natural cellulosic pads impractical.
With the foregoing in mind, it is the primary object of this invention to provide an evaporative cooler pad formed from natural cellulosic lightweight elongate segments which has an increased evaporative efficiency without substantially increasing the thickness of the pad.
It is another object of the present invention to provide an evaporative cooler pad formed from natural cellulosic lightweight elongate segments where the evaporative efficiency of the pad can be retained, but the pad can be produced to thinner dimensions.
It is another object of the present invention to provide an evaporative cooler pad formed from natural cellulosic lightweight elongate segments where the evaporative efficiency of the pad can be increased without restricting air flow through the pad.
It is still another object of this invention to provide a method of forming the aforesaid evaporative cooling pad.